It’s too soon to know, of course, whether Jared Loughner will invoke an insanity defense during his trial.

But press accounts have noted behavior that seems strange, if not downright insane. Case in point: His rather incoherent rantings about the evils of America’s currency and grammatical structure.

Still, it won’t be easy for him to establish that he is legally insane. Here’s an article in the Examiner.com that analyzes a possible Loughner insanity defense; click here for another article, from the AP.

The “Unabomber” Ted Kaczynski, who was represented by Loughner’s lawyer, Judy Clarke, was diagnosed as a paranoid schizophrenic. But Kaczynski was still declared competent to stand trial and convicted on 10 criminal counts, the Examiner.com reports.

Loughner is being tried in federal court; under federal law, a defendant must prove that he was so mentally impaired at the time of an offense that he didn’t know right from wrong, according to the Examiner.

We checked in with Mark Heyrman, an instructor at the University of Chicago law school who specializes in mental-health law and represents clients with mental illness.